A number of devices are known to plug apertures in tanks, pipes, automobiles, water-going vessels and the like. However, the prior art devices in many cases cannot be used in connection with hard to bond and complex surfaces.
A common practice of repairing holes in panels is to form a tapered recess in the composite material around the hole. Disk-shaped layers of structural fiber cloth of different diameters are set into the recess. The fibers of each layer are oriented at a different angle to the fibers of the adjoining layer. The layers are then secured in place by the use of high strength adhesive. A problem with these adhesives is that they require a long cure time. Also, this method of repair requires a highly trained technician and the repaired area relies totally on the adhesives to transfer the design load across the repair. A similar technique is disclosed by U.S. Pat. No. 4,544,036, granted Nov. 19, 1985, to Cosby M. Newsom. Other repair techniques, known in the patent literature are disclosed by U.S. Pat. No. 4,517,038, granted May 14, 1985 to Robert W. Miller, and U.S. Pat. No. 4,560,428, granted Dec. 24, 1985 to George O. Sherrick and Joseph R. Rosenthal.
U.S. Pat. No. 3,470,048 to Jones discloses a method of patching car bodies with an adhesive repair patch in combination with a plastic filler material containing a catalyst.
U.S. Pat. No. 4,486,254 to Zinimon discloses a heat activated patch or repair composition for metal objects. The patch or repair composition is heat activated by heating from the opposite surface to a temperature of from about 250.degree. to 500.degree. F.
U.S. Pat. No. 4,916,880 to Westerman discloses the combination of shaped inserts and adhesives for repairing a hole in a panel of composite materials.
European Patent Application No. 0,016,248 to Dainippon Ink & Chemical, discloses a process for producing prepregs which can be used in the present invention.
It is to be understood that the term "fabric" as used herein is intended to include a knitted cloth, for example, plain jersey knit, interlock, ribbed, cross float jersey knit or weft knit, and the like, or woven into a fabric, for example of plain weave, satin weave, twill weave, basket weave, and the like. The woven fabric may combine the various fibers of the present invention, the fabric may also be in the form of a non-woven material such as a mat, fluff or batting of fibers such as described above. The fabric may include a wool-like fluffy material produced from high modulus fibers. The substrate in the form of a batting or wool-like fluff may be prepared by conventional needle-punching means.
The term "installation" as used herein is meant to relate to machinery, building structures, tanks, and the like which are metallic or plastic.
The term "parts" includes the components of the installation or vehicles as well as tools.
The term "photocurable" includes means curable upon exposure to UV radiation as well as electron beam radiation.